Mod 4: Make Your TS9 or SD-1 More Transparent
Tools and Parts for This Mod
• 1k Ω 1/4-watt resistor (one for a TS9, two for an SD-1)
• A1k Ω audio potentiometer
• .22 μF capacitor
• 2.2 μF electrolytic capacitor
• 1" piece of jumper wire
• Two 3" pieces of wire
• Pot knob for the new pot
Have you ever noticed how, when you turn your TS9’s or SD-1’s tone
knob up, it sounds like the pedal is boosting frequencies? That’s
because it is. Both pedals have an active tone control. Some players
like that, but others prefer a passive tone control. This mod shows you
how to install a passive tone control to make your Tube Screamer or
Super Overdrive sound much more transparent.
Fig. 6: Schematic for the TS9 and SD-1 transparency mod.
The steps for installing a passive
tone control are pretty much
the same for a Tube Screamer
and a Super Overdrive (see Fig.
6 for a reference schematic), so
we’ll cover both together here
and note any divergences within
the appropriate step.
Photo 13 (left): Remove the indicated wires and components in your TS9. Photo 14 (right): Remove the indicated wires and components in your SD-1.
1. For a TS9: Remove wires 6,
7, and 8, as well as components
R11 and C9 (see Photo 13).
For an SD-1: Remove wires 5,
8, and 11, as well as components
C5 and R8 (see Photo 14).
2. Remove the old 20k Ω
tone pot.
3. TS9: Attach a 3" wire from
lug 2 of your new A1k Ω pot
to the hole where wire 7 used
to connect to the circuit board.
SD-1: Remove R7 and replace
it with a 1k Ω resistor. Then
solder one end of a 3" wire to
lug 2 of your new A1k Ω pot,
and solder the other end where
wire 5 used to connect to the
circuit board.
Photo 15 (left): Connect a 3" wire from the new tone pot to hole 7 on your TS9’s circuit board. Photo 16 (right): Solder one leg of the .22 µF cap to lug 1 of the tone pot, then attach a 3" wire to the other leg.
4. TS9: Remove C5.
SD-1: Remove C4.
5. Stick one leg of your new
.22 μF capacitor through lug 1
of your new pot and solder it
in place. Attach another 3" wire
to the open leg of the cap (see
Photo 16). Note: When making
a connection like this, I suggest
stripping a little extra off of the
wire and wrapping it around the
cap’s leg before soldering it. It’s
also a good idea to put electrical
tape or heat-shrink wrap around
bare spots such as this one.
6. TS9: Solder the other end of
the 3" wire into the negative hole
where C5 used to be (the negative
hole is the one that’s not next
to the plus sign). See Photo 17.
SD-1: Solder the other end of
the 3" wire to the sleeve lug of
the output jack. See Photo 18
Photo 17 (left): Solder the other end of the 3" wire to the negative hole vacated by C5 in your TS9. Photo 18 (right): Solder the other end of the 3" wire to the sleeve lug of you SD-1’s output jack.
7. TS9: Attach the 1" piece of
wire from where wire 6 used
to be to the hole where wire 8
used to be.
SD-1: Attach the 1" piece of
wire from where wire 8 used to
be to the hole where wire 11
used to be. See Photo 19.
Photo 19: (left): Jumper holes 8 and 11 on your SD-1 circuit board. Photo 20 (right): Install the 1k Ω resistor and 2.2 µF cap in your Tube Screamer.
8. TS9: Solder your new 1k Ω
resistor where C9 used to be
and place your 2.2 μf electrolytic
capacitor where R11 used
to be (see Photo 20).
Photo 21: Install the 1k Ω resistor and 2.2 µF cap in your Super Overdrive. Note:
Make sure the negative side of
your electrolytic capacitor is closest
to your Tube Screamer’s IC
chip, and that the positive side
is closest to the 1k Ω resistor you
just installed. The negative side
is usually signified by a stripe on
the cap, and the positive side is
almost always the long leg.
SD-1: Solder your 1k Ω resistor
where C5 used to be and your
2.2 μF electrolytic capacitor
where R8 used to be.
Note: Make sure the capacitor’s
negative side (the short leg or the
short leg near the stripe on the
cap) is in the hole closest to the
edge of the circuit board, and the
positive side (the long leg) is
closest to the newly placed 1k
Ω resistor.